The present invention relates to plumbing systems, and fittings for use therein, for routing waste from a plurality of plumbing fixtures to a sewer, and for venting sewer gases to the atmosphere. Proper routing of waste and venting of gases within plumbing systems are critical to sanitary functioning. It is common for municipalities to establish building codes for sanitary facilities. One element commonly occurring in such building codes, as for example, the city of Houston, Tex. building Code, is that "continuous waste and vent" be provided for water closets. The phrase "continuous waste and vent" refers to the vertical spatial relationship between the waste line receiving waste from a water closet and the vent line associated therewith. For the waste line and vent line to be continuous within the meaning of the phrase "continuous waste and vent", the waste line and vent line must be in communication at the point wastes from the water closet enter the system, and the waste line must pass downward and the vent line must pass upward at angles such that neither the waste line nor the vent line deviate more than 45 from vertical. That is, the waste line must be aligned vertically downward to provide at least 45.degree. slope such that solid wastes will not settle and accumulate therein, and the vent line must be aligned vertically upward to provide at least 45.degree. slope such that solid wastes from the water closet will not enter the vent line and cause plugging or restriction of gas flow. Among the effects of improper plumbing of waste and vent lines is, flow in the vent line may become restricted, causing a "gurgling" noise or in severe cases the vent line may become plugged, resulting in a blow-back of sewer gases into the water closet bowl. A restricted or plugged waste line will result in improper flushing, or overflow, of wastes from the water closet bowl. Improper plumbing of waste and vent lines for other plumbing fixtures will result in similar problems of gas blow-back, and failure of waste drainage.
One common practice, in the plumbing art, for providing "continuous waste and vent" for plumbing fixtures is to provide substantially vertical waste and vent lines for each plumbing fixture. The vent lines are passed upward to an elevation above the plumbing fixtures, whereupon they may be joined into a common vent. The waste lines are passed downward, below the floor level upon which the fixtures are located, whereupon they may be joined into a common waste line which enters a sewer. The disadvantage of this arrangement is that each waste line must penetrate the floor at the location of the plumbing fixture and be directed to the common waste line, or to the sewer, below floor level. For grade level floors, this requires that accurately plumbed waste lines be installed below grade in a situation wherein their alignment is easily disturbed by collateral work, such as pouring concrete, carpenter work, etc. For floors above grade level, the waste lines extend below floor level, thus requiring additional carpenter work, such as providing a chase or false ceiling, to conceal the pipes.
In order to avoid problems associated with connecting waste lines from each plumbing fixture below floor level, plumbing fittings and plumbing systems have been devised wherein waste lines from a plurality of plumbing fixtures are brought together above floor level such that only one common waste line penetrates the floor, and such that water closets and brach waste lines are properly vented. Those known to applicant are shown as U.S. Pat. Nos. 4,073,018; 3,711,128; and 3,495,281. The fitting of U.S. Pat. No. 4,073,018 provides adequate drainage and venting, but is extremely complex, comprising two vertical, concentric pipes with a plurality of vent pipes in the annulus and a plurality of horizontal pipes in communication with the interior of the vertical pipes and with the vent pipes. This device is difficult to construct, and expensive.
The plumbing fitting of U.S. Pat. No. 3,711,128 provides for connection of a plurality of plumbing fittings from a single storey to a single vertical drain, with adequate venting. However, the fitting does not accommodate waste drainage from an upper storey. Further the fitting is very wide in horizontal cross-section. This width requires an extremely wide chase to conceal the fitting, thus adding materialy to cost of installation.
The fitting of U.S. Pat. No. 3,495,281 is designed to accommodate a plurality of plumbing fittings and wastes from an upper storey. However, because of height requirements to accommodate standard plumbing fixtures, the fitting cannot accommodate both a standard and back-flush water closet and a standard above-the-floor bathtub drain, unless the bathtub drain is set below floor level.
In the design of plumbing systems for draining and venting plumbing fixtures, care must be taken to provide "continuous waste and vent" for water closets, and to avoid "flat venting". The term "flat vented" refers to the condition wherein the waste line and/or the vent line deviate from vertical by more than 45.degree. such that wastes may either settle in the waste line or enter the vent line, causing plugging or restriction of flow.
Plumbing fixtures manufactured within the United States are manufactured to standard dimensions, such that similar fixtures from different manufactures may be freely substituted with the plumbing systems. For example, standard back-flush water closets have a discharge designed to accommodate a 3 inch diameter (I.D.) waste line, and the centerline of said discharge is 4 inches above the bottom of said water closet. Also, standard above-the-floor bathtubs have a bottom drain which is 31/4inches above the floor, and which accommodates a 2 inch I.D. waste line. The plumbing systems of the present invention are designed for use with such standard plumbing fixtures.